Taco on a Platter

1 medium onion , chopped

1 (14 ounce) can tomato paste

1 (14 ounce) can crushed tomatoes

2 tablespoons chili powder

1 teaspoon ground cumin

1/2 teaspoon garlic powder

2 teaspoons salt

1 (28 ounce) can pork and beans in tomato sauce

2 cups corn chips, broken

2 cups cooked long-grain rice , hot

2 cups medium cheddar , grated

1 medium red onion , chopped

1 head iceberg lettuce , shredded

3 medium tomatoes , chopped

1/3 cup sliced ripe olives , pitted